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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 465-468页

作者： ZHANG YuChao1, XING ZhiGang2, MA ZiGuang2, CHEN Yao2, DING GuoJian2, XU PeiQiang2, DONG ChenMing3. CHEN Hong2 & LE XiaoYun1 1 School of physics and Nuclear Energy Engineering, Beihang University, beijing 100190, china 2 Renewable Energy Laboratory, Institute of physics, chinese academy of sciences, beijing 100190, china 3.School of Information and Communication, Tianjin Polytechnic University, Tianjin 3.0160, china School of physics and Nuclear Energy Engineering Beihang University Beijing China Renewable Energy Laboratory Institute of Physics Chinese Academy of Sciences Beijing China School of Information and Communication Tianjin Polytechnic University Tianjin China

GaN epifilms are grown on the patterned sapphire substrates (PSS) (0001) and the conventional sapphire substrates (CSS) (0001) by metal-organic chemical vapor deposition (MOCVD) using a novel two-step growth. High resolution X-ray diffraction (HR-XRD) is used to investigate the threading dislocation (TD) density of the GaN epifilms. The TD density is calculated from the ω-scans full width at half maximum (FWHM) results of HR-XRD. The edge dislocation destiny of GaN grown on the PSS is 2.7×108 cm-2, which is less than on the CSS. This is confirmed by the results of atomic force microscopy (AFM) measurement. The lower TD destiny indicates that the crystalline quality of the GaN epifilms grown on the PSS is improved compared to GaN epifilms grown on the CSS. The residual strains of GaN grown on the PSS and CSS are compared by Raman Scattering spectra. It is clearly seen that the residual strain in the GaN grown on PSS is lower than on the CSS.

关键词： GaN patterned sapphire substrate threading dislocation XRD

Progress in modeling of fluid flows in crystal growth processes

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Progress in Natural Science:Materials International 2008年第12期18卷 1465-1473页

作者： Qisheng Chen Yanni Jiang Junyi Yan Ming Qin Institute of Mechanics.chinese academy of sciences,beijing 100190,china Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

Modeling of fluid flows in crystal growth processes has become an important research area in theoretical and applied *** crystal growth processes involve fluid flows,such as flows in the melt,solution or *** modeling has played an important role in developing technologies used for growing semiconductor crystals for high performance electronic and optoelectronic *** application of devices requires large diameter crystals with a high degree of crystallographic perfection,low defect density and uniform dopant *** this article,the flow models developed in modeling of the crystal growth processes such as Czochralski,ammono- thermal and physical vapor transport methods are *** the Czochralski growth modeling,the flow models for thermocapillary flow,turbulent flow and MHD flow have been *** the ammonothermal growth modeling,the buoyancy and porous media flow models have been developed based on a single-domain and continuum approach for the composite fluid-porous layer *** the physical vapor transport growth modeling,the Stefan flow model has been proposed based on the flow-kinetics theory for the vapor *** addition,perspectives for future studies on crystal growth modeling are proposed.

关键词： Modeling Crystal growth Fluid flow Czochralski growth Ammonothermal growth Physical vapor transport

GAUSS-SEIDEL-TYPE MULTIGRID METHODS

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Journal of Computational Mathematics 2003年第4期21卷 421-434页

作者： Zhao-hui Huang Qian-shun Chang (academy of Mathematics and System sciences, chinese academy of sciences, {3. 100080, china) academy of Mathematics and System sciences Chinese Academy of Sciences 北京 100080

By making use of the Gauss-Seidel-type solution method, the procedure for computing the interpolation operator of multigrid methods is simplified. This leads to a saving of computational time. Three new kinds of interpolation formulae are obtained by adopting different approximate methods, to try to enhance the accuracy of the interpolatory operator. A theoretical study proves the two-level convergence of these Gauss-Seidel-type MG methods. A series of numerical experiments is presented to evaluate the relative performance of the methods with respect to the convergence factor, CPU-time(for one V-cycle and the setup phase) and computational complexity.

关键词： Multigrid methods Gauss-Seidel solution Interpolation formula Convergence.

Sea surface temperature east of Australia:A predictor of tropical cyclone frequency over the western North Pacific?

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chinese Science Bulletin 2011年第2期56卷 196-201页

作者： ZHOU BoTao 1,2 & CUI Xuan 3.1 National Climate Center,china Meteorological Administration,beijing 100081,china 2 Nansen-Zhu International Research Center,Institute of Atmospheric {3.,chinese academy of sciences,beijing 100029,china 3.National Meteorological Center,china Meteorological Administration,beijing 100081,china National Climate Center China Meteorological Administration Beijing China Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China National Meteorological Center China Meteorological Administration Beijing China

The relationship between sea surface temperature (SST) east of Australia and tropical cyclone frequency over the western North Pacific (WNPTCF) is analyzed by use of observation *** WNPTCF from June to October is correlated negatively to spring SST east of *** the spring SST is in the positive phase,a cyclonic circulation anomaly in the upper troposphere and an anticyclonic circulation anomaly in the lower troposphere prevail over the western North Pacific from June to October,concurrent with an anomalous atmospheric subsidence and an enlarged vertical zonal wind *** conditions are unfavorable for tropical cyclone genesis,and thus WNPTCF *** negative phase of the spring SST east of Australia leads to more tropical cyclones over the western North *** spring SST east of Australia may give rise to simultaneous change in tropical atmospheric circulation via the teleconnection wave train,and then subsequently affect atmospheric circulation variation over the western North Pacific.

关键词：热带气旋北太平洋澳大利亚西部海面温度热带大气环流预测频率

Approaches to improving critical current density of YBCO superconducting thick films deposited by electrophoresis

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Science china(physics,Mechanics & Astronomy) 2004年第2期47卷 165-172页

作者： ZHU Yabin1,2, ZHOU Yueliang2, LIU Zhen2, WANG Shufang2, CHEN Zhenghao2, L?Huibin2, YANG Guozhen2, XIAO Ling3. REN Hongtao3. JIAO Yulei3.& ZHENG Minghui3.1. Department of physics, College of Science, beijing Jiaotong University, beijing 100044, {3. 2. Laboratory of Optical physics, Institute of physics and Center for Condensed Matter physics, chinese academy of sciences, beijing 100080, {3. 3. General Research Institute for Nonferrous Metals, beijing 100088, {3. Correspondence should be addressed to Zhu Yabin (email: ybzhu@***) Department of physics College of Science Beijing Jiaotong University Beijing China Laboratory of Optical physics Institute of physics and Center for Condensed Matter physics Chinese Academy of Sciences Beijing China General Research Institute for Nonferrous Metals Beijing China

Fabrication of YBCO superconducting thick films by electrophoresis has been widely reported. However, the value of critical current density (J c) is far from what the practical application requires. The superconducting thick films are obtained using top-seeded melt growth method with different proportional Y2BaCuO5 (Y211) addition. High-pressure oxygen has been used in the annealing process to improve the uniformity of the oxygen content in the superconducting thick films. When 40mol% Y211 powder is added to the YBa2Cu3.7–5 (Y123. powder,J c for the superconducting thick film by approaches described above reaches 7.008×103.A/cm2 (77 K, 0 T), which is greater than the value ever reported.

关键词： YBCO thick films, electrophoretic deposition, melt-textured.

Latest progress on interactions between VLF/ELF waves and energetic electrons in the inner magnetosphere

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Science china Earth sciences 2010年第3期53卷 317-326页

作者： XIAO FuLiang1,2, ZONG QiuGang3. SU ZhenPeng4, TIAN Tian3.& ZHENG HuiNan4 1 School of physics and Electronic sciences, Changsha University of Science and Technology, Changsha 410004, china 2 State Key Laboratory of Space Weather, {3., beijing 100190, china 3.Institute of Space physics and Applied Technology, Peking University, beijing 100871, china 4 CAS Key Lab for Basic Plasma Science, School of Earth and Space sciences, University of Science and Technology of china, Hefei 23.026, china School of physics and Electronic sciences Changsha University of Science and Technology Changsha China State Key Laboratory of Space Weather Chinese Academy of Sciences Beijing China Institute of Space physics and Applied Technology Peking University Beijing China CAS Key Lab for Basic Plasma Science School of Earth and Space Sciences University of Science and Technology of China Hefei China

Interactions between very/extremely low frequency (VLF/ELF) waves and energetic electrons play a fundamental role in dynamics occurring in the inner magnetosphere. Here, we briefly discuss global properties of VLF/ELF waves, along with the variability of the electron radiation belts associated with wave-particle interactions and radial diffusion. We provide cases of electron loss and acceleration as a result of wave-particle interactions primarily due to such waves, and particularly some preliminary results of 3. evolution of phase space density from our currently developing 3. code. We comment on the existing mechanisms responsible for acceleration and loss, and identify several critical issues that need to be addressed. We review latest progress and suggest open questions for future investigation.

关键词： wave-particle interaction VLF/ELF waves energetic electrons acceleration and loss inner magnetosphere

A one-dimensional heat transfer model of the Antarctic Ice Sheet and modeling of snow temperatures at Dome A, the summit of Antarctic Plateau

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Science china Earth sciences 2010年第5期53卷 763-772页

作者： CHEN BaiLian1,3. ZHANG RenHe2, SUN ShuFen1, BIAN LinGen2, XIAO CunDe4,2 & ZHANG TingJun5 1 Institute of Atmospheric physics, chinese academy of sciences, beijing 100029, {3. 2 chinese academy of Meteorological sciences, beijing 100081, {3. 3.Graduate University of chinese academy of sciences, beijing 100049, {3. 4 Cold and Arid Regions Environmental and Engineering Research Institute, chinese academy of sciences, Lanzhou 73.000, {3. 5 The National Snow and Ice Data Center, University of Colorado, Boulder, CO 803.9-0449, USA Institute of Atmospheric physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China chinese academy of Meteorological sciences Beijing China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China The National Snow and Ice Data Center University of Colorado Boulder USA

A vertical one-dimensional numerical model for heat transferring within the near-surface snow layer of the Antarctic Ice Sheet was developed based on simplified parameterizations of associated physical processes for the atmosphere, radiation, and snow/ice systems. Using the meteorological data of an automatic weather station (AWS) at Dome A (80°22′S, 70°22′E), we applied the model to simulate the seasonal temperature variation within a depth of 20 m. Comparison of modeled results with observed snow temperatures at 4 measurement depths (0.1, 1, 3. 10 m) shows good agreement and consistent seasonal variations. The model results reveal the vertical temperature structure within the near-surface snow layer and its seasonal variance with more details than those by limited measurements. Analyses on the model outputs of the surface energy fluxes show that: 1) the surface energy balance at Dome A is characterized by the compensation between negative net radiation and the positive sensible fluxes, and 2) the sensible heat is on average transported from the atmosphere to the snow, and has an evident increase in spring. The results are considered well representative for the highest interior Antarctic Plateau.

关键词： Antarctic Ice Sheet near-surface layer energy transfer numerical model

Simulating Hydrologic Changes with Climate Change Scenarios in the Haihe River Basin

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Pedosphere 2005年第5期15卷 53-58页

作者： YUAN Fei 1,2, XIE Zheng-Hui1,* 2, LIU Qian1 and XIA Jun 3.1LASG, Institute of Atmospheric physics, chinese academy of sciences, beijing 100029 ({3.). 2 College of Water Resources and Environment, Hohai University, Nanjing 210098 ({3.)3.Institute of Geographical Science & Natural Resources, chinese academy of sciences, beijing 100101 ({3.) Institute of Atmospheric physics Chinese Academy of Sciences LASG CAS Beijing 100029 Institute of Geographical Science & Natural Resources Chinese Academy of Sciences Beijing 100101

Climate change scenarios, predicted using the regional climate modeling system of PRECIS (providing regional cli-mates for impacts studies), were used to derive three-layer variable infiltration capacity (VIC-3.) land surface model forthe simulation of hydrologic processes at a spatial resolution of 0.25° × 0.25° in the Haihe River Basin. Three climatescenarios were considered in this study: recent climate (1961-1990), future climate A2 (1991-2100) and future climateB2 (1991-2100) with A2 and B2 being two storylines of future emissions developed with the Intergovernmental Panel onClimate Change (IPCC) special report on emissions scenarios. Overall, under future climate scenarios A2 and B2, theHaihe River Basin would experience warmer climate with increased precipitation, evaporation and runoff production ascompared with recent climate, but would be still likely prone to water shortages in the period of 203.-2070. In addition,under future climate A2 and B2, an increase in runoff during the wet season was noticed, indicating a future rise in theflood occurrence possibility in the Haihe River Basin.

关键词： climate change regional climate modeling system runoff VIC-3. model

A new approach of cascade utilization of the chemical energy of fuel

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Progress in Natural Science:Materials International 2006年第5期16卷 518-523页

作者： HAN Wei, JIN Hongguang and LIN Rumou ( Institute of Engineering Thermophysics, chinese academy of sciences, beijing 100080, {3. Graduate School of the chinese academy of sciences, beijing 100080, {3.) Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100080 China Graduate School of the chinese academy of sciences Beijing 100080 China

The indirect release of chemical energy of fuel is investigated, and a new mechanism is proposed to identify the cascade utilization of chemical energy of fuel more clearly. Based on the concept of energy level, the internal phenomenon of the indirect chemical energy release is disclosed, and the equations of energy level describing the utilization of chemical energy and thermal energy during the indirect chemical energy release process are obtained. From theoretical analysis, we find that the superiority of the indirect chemical energy release of fuel comes from the cascade utilization of the fuel's chemical energy. Moreover, the cascade utilization of chemical energy is verified by the investigation of CRGT (chemically recuperated gas turbine). As a result, the thermal exergy obtained from the chemical energy release of fuel increases by 2 % -3.% . The results obtained here may help a deeper understanding of indirect chemical energy release of fuel and provide a theoretical basis for the synthesis of innovative energy systems.

关键词： chemically recuperated gas turbine methane/steam reforming chemical energy level cascade utilization.

2002:The extra-strong warm winter event in North Asia and its accompanying anomalous atmospheric circulation

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chinese Science Bulletin 2003年第10期48卷 1031-1033页

作者： WANG Huijun LASG, Institute of Atmospheric physics, chinese academy of sciences, beijing 100029, {3. LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

Features of an extra-strong warm winter event in North Asia in 2002 and its accompanying anomalous atmospheric circulation were studied through diagnosis on the atmospheric reanalysis data set. Results show that the winter of 2002 is of the warmest in the recent 54 years in North Asia, which was caused by both decadal scale and interannual scale variability. The interannual variability is proved to be as the main cause for the event, and it is related to the global scale atmospheric circulation anomalies, with the strongest of them in the Eastern Hemisphere and in the middle and high latitude region of the Southern Hemisphere.

关键词：大气环流亚洲北部高强度暖冬现象天气资料